ABSTRACT: Circadian biology regulates inflammatory responses in mice via the clock protein REVERBα, resulting in altered mortality and morbidity. The influence of this immune-modulation pathway in humans is unclear, but may affect outcomes after transplant. We sought to determine whether the circadian clock affects primary graft dysfunction after lung transplantation, and the role of the clock protein REVERBα. In this study we investigated the action of a synthetic REVERB ligand, (GSK4112) in human monocyte-derived macrophages.

Similar Datasets

Project description:The circadian clock acts at the genomic level to coordinate internal behavioral and physiologic rhythms via the CLOCK-BMAL transcriptional heterodimer. Although the nuclear receptors REV-ERBα and β have been proposed to contribute to clock function, their precise roles and importance remain unresolved. To establish their regulatory potential we generated comparative cistromes of both Rev-erb isoforms, which revealed shared recognition at over ~50% of their total sites and extensive overlap with the master clock regulator Bmal. While Rev-erbα has been shown to directly regulate Bmal expression, the cistromic analysis reveals a more profound connection between Bmal and Rev-erbα and β regulatory circuits than previously suspected. Genes within the intersection of the Bmal and Rev-erb cistromes are highly enriched for both clock and metabolic functions. As predicted by the cistromic analysis, dual depletion of Rev-erbα/β function by creating double-knockout mice (DKOs) profoundly disrupted circadian expression of core clock and lipid homeostatic genes. As a result, DKOs show strikingly altered circadian wheel-running behavior and deregulated lipid metabolism. These data reveal an integral role of Rev-erbα/β in clock function as well as provide a cistromic basis for the integration of circadian rhythm and metabolism. Identification of Reverb alpha and Reverb beta binding sites in mouse liver at ZT8

Project description:The circadian clock acts at the genomic level to coordinate internal behavioral and physiologic rhythms via the CLOCK-BMAL transcriptional heterodimer. Although the nuclear receptors REV-ERBα and β have been proposed to contribute to clock function, their precise roles and importance remain unresolved. To establish their regulatory potential we generated comparative cistromes of both Rev-erb isoforms, which revealed shared recognition at over ~50% of their total sites and extensive overlap with the master clock regulator Bmal. While Rev-erbα has been shown to directly regulate Bmal expression, the cistromic analysis reveals a more profound connection between Bmal and Rev-erbα and β regulatory circuits than previously suspected. Genes within the intersection of the Bmal and Rev-erb cistromes are highly enriched for both clock and metabolic functions. As predicted by the cistromic analysis, dual depletion of Rev-erbα/β function by creating double-knockout mice (DKOs) profoundly disrupted circadian expression of core clock and lipid homeostatic genes. As a result, DKOs show strikingly altered circadian wheel-running behavior and deregulated lipid metabolism. These data reveal an integral role of Rev-erbα/β in clock function as well as provide a cistromic basis for the integration of circadian rhythm and metabolism. Total RNA was obtained from livers of wild-type and Liver-specific Reverb alpha/beta double knockout mice at ZT 0, 4, 8, 12, 16, and 20.

Project description:Circadian clocks drive ~24 hr rhythms in tissue physiology. They rely on transcriptional/translational feedback loops driven by interacting networks of clock complexes.To gain insights into the role of the mammary clock, circadian time-series microarrays were performed to identify rhythmic genes in vivo. Breast tissues were isolated at 4 hr intervals for two circadian (24 hourly) cycles, from mice kept under constant darkness to avoid any light- or dark-driven genes.

Project description:There is growing appreciation that the feeling of well-being, alterations in mood and susceptibility to a variety of medical disorders depend on the proper expression of the master circadian clock and the synchrony among the other oscillators found in many peripheral tissues. To improve our understanding of the role of peripheral oscillators, an improved understanding of the molecular machinery sub-serving the circadian variation in gene expression is essential. Our long-term goal is to understand the molecular mechanisms that initiate circadian gene expression following external stimulation in the mammalian pineal gland. Are all or just some of the "circadian clock" genes induced by NE, cAMP, or cGMP? In this project we compare a series of gene expression patterns using DNA microarray in response to cAMP, cGMP and NE stimulation to understand why NE does not initiate circadian rhythms in the rat pineal gland. As a preliminary experiment we will compare gene expression 0, 1, and 4 h after start of chemical stimulation. A failure of NE to initiate circadian rhythms is due to failure of activation of certain "circadian clock" genes. We found that circadian rhythms are initiated by stimulation of cAMP or cGMP analogue in the rat pineal gland, while norepinephrine (NE) stimulation only moderately induce Period1 mRNA (one of "circadian clock" genes) 24 h after start of stimulation. From these results we hypothesize that external stimulation activates some "circadian clock" genes simultaneously, and that failure of circadian rhythm initiation following NE stimulation is due to insufficient "circadian clock" genes activations. Male rats of wistar strain are kept in 12h-12h light dark cycles at least for one week before start of experiments. Pineal glands are removed from animals and placed in the culture dish. Rat pineal glands are cultured for 3 days before chemical stimulation. On the day of experiment, the pineal cultures are stimulated using one of NE, cAMP and cGMP analogues for 1 or 4 h before harvest. The samples are immediately frozen and total RNA are extracted from each group which are from a pool of 8 pineal glands using Trizol reagent (Invitrogen). Concentrations of total RNA are determined using spectrophotometer, and six microgram of total RNA is aliquoted in each sample tube for further analysis. Since we already have Affymetrix Rat Genome U34A array GeneChips, we would like to send Chips as well as our total RNA samples. Experiment Overall Design: as above

Project description:Circadian clocks coordinate time-of-day specific metabolic and physiological processes to maximize performance and fitness. In addition to light, which is considered the strongest time cue to entrain animal circadian clocks, metabolic input has emerged as an important signal for clock modulation and entrainment, especially in peripheral clocks. Circadian clock proteins have been to be substrates of O-GlcNAcylation, a nutrient sensitive post-translational modification (PTM), and the interplay between clock protein O-GlcNAcylation and other PTMs, like phosphorylation, is expected to facilitate the regulation of circadian physiology by metabolic signals. Here, we used mass spectrometry proteomics to identify PTMs on PERIOD, the key biochemical timer of the Drosophila clock, over the circadian cycle.

Project description:In mammals circadian clocks are present not only in the hypothalamus but also in all peripheral organs where they rhytmically control tissue specific biological processes. Here, the transcriptome of the mouse colon mucosa was analysed around the clock to identify genes whose gne expression is under circadian regulation.

Project description:Genome-wide expression analysis of two circadian oscillatory mechanisms in the mouse liver; To identify the genes of which the circadian expression is regulated by endogenous glucocorticoids, we performed DNA microarray analysis using hepatic RNA from adrenalectomized (ADX) and sham-operated mice. Mice were housed in a 12:12 h light-dark cycle (LD12:12; lights on at zeitgeber time (ZT) 0) for at least two weeks before the day of the experiment. Liver samples were dissected, quickly frozen, and stored in liquid nitrogen. Total RNA was purified from pools of 3 animal tissues collected at each time-point using ISOGEN (Nippon Gene Co., Ltd., Japan). Hybridization to Affymetrix GeneChip (MG-U74Av2) arrays proceeded as described (Oishi K et al., J Biol Chem, 278, 41519-41527, 2003). The average difference (AD) value for each gene was provided by GeneChip software. To identify putative glucocorticoid-regulated circadian genes, we compared AD values between two time points (ZT2 and ZT14) in sham operated and in ADX mice. We applied three criteria to the selection of putative glucocorticoid-regulated circadian genes: (i) the AD value is marked as “present” by the GeneChip software in at least one of two time points, (ii) the AD value exhibits a 2-fold or greater change in sham-operated mice and (iii) the fold change is below 2-fold in ADX mice. We identified 169 genes that fluctuated between day and night in the livers of sham-operated mice. Among these, 100 lost circadian rhythmicity in ADX mice. On the other hand, the circadian expression of clock or clock-related genes such as mPer2 and DBP remained almost totally intact in the liver of ADX mice. The present study showed that the circadian expression of one type of liver genes in the mouse is governed by core components of the circadian clock such as CLOCK and BMAL1, and the other depends on endogenous glucocorticoids.

Project description:The circadian clock is comprised of proteins that form negative feedback loops, which regulate the timing of global gene expression in a coordinated 24 hour cycle. As a result, the plant circadian clock is responsible for regulating numerous physiological processes central to growth and survival. To date, most plant circadian clock studies have relied on diurnal transcriptome changes to elucidate molecular connections between the circadian clock and observable phenotypes in wild-type plants. Here, we have combined high-throughput RNA-sequencing and mass spectrometry to comparatively characterize the lhycca1, prr7prr9, gi and toc1 circadian clock mutant rosette transcriptome and proteome at the end-of-day and end-of-night.

Project description:Nuclear receptor Reverb alpha is a component of circadian rythm which could be evolved in cardioprotection strategy. We test if pharmacological modulation of these target could be suitable for cardioprotection after ischemia reperfusion injury We used microarrays to detail the global programme of gene expression Overall design: heart ischemia reperfusion were performed using Langendorff isolated heart model and twenty minutes stop flow ishemia with twenty minutes reperfusion.

Project description:Nuclear receptor Reverb alpha is a component of circadian rythm which could be evolved in cardioprotection strategy. We test if pharmacological modulation of these target could be suitable for cardioprotection after ischemia reperfusion injury We used microarrays to detail the global programme of gene expression Overall design: Heart ischemia reperfusion were performed using Langendorff isolated heart model and twenty minutes stop flow ishemia with twenty minutes reperfusion.